Effects Of Isovalerate On Rumen Development In Pre- And Post-weanning Dairy Calves

In order to evaluate the effccts of different level isovaleric acid on development of rumen, twenty-four Chinese Hostein male calves about 10 days after birth(45.09±0.90 kg) were chosen and divided into four groups, control group, LIV、MIV、HIV were supplemented with four concentrations (0,3,6 and 9 g/d) of isovaleric acid. Before feeding, the calves were weighed respectively and slaughtered on 30 d,60 d and 90 d after birth. The results showed that ① weights of each stomach and total stomach of calves in groups of LIV, MTV, HIV were higher than that of control group significantly(P<0.05) at each day of age.②The percentage of rumen of calves in groups MIV, HIV were higher than that of control group significantly (P< 0.05) at each day of age, while no significant differences were found between MIV, HIV(P> 0.05). ③The morphology of each part of rumen of bull calves in groups MIV-. HIV were higher than that of control group significantly (P< 0.05) at each day of age. ④The total volatile fatty acids, acetic acid, acetic acid and acetic acid in MIV and HIV groups were significantly higher than those in Control group (P< 0.05), and the acid, ammonia nitrogen and pH were significantly lower than that of Control group (P< 0.05). The pH, Acetate, A:P, Ammonia N in rumren of bull calves in groups MIV, HIV were higher than that of control group significantly (P< 0.05) at each day of age. ⑤The Butyrivibrio fibrisolvens in rumren of bull calves at each day of age, Ruminococcus albus, Ruminococcus flavefaciens, Fibrobacter succinogenes at 60 and 90 days of age in groups MIV, HIV were higher than that of control group significantly (P< 0.05), while no significant differences were found between MTV, HIV(P>0.05).⑥The filter paper activity in rumren of bull calves at each day of age, a-amylase, p-amylase at 30 days of age, carboxymethyl cellulase, cellobiose enzymes, xylanase, pectinase at 60 and 90 days of age in groups MIV, HIV were higher than that of control group significantly (P< 0.05). ⑦ The expression of growth hormone, insulin receptor mRNA of each part of rumen of bull calves in groups MIV, HIV were higher that of control group significantly (P< 0.05), while no significant differences were found between MIV, HTV(P> 0.05).⑧The expression of insulin-like growth factor 1 receptor mRNA in dorsal sac, anterior dorsal blind sac, anterior ventral blind sac, posterior ventral blind sac of rumen of bull calves in groups MIV, HIV were higher that of control group significantly (P< 0.05), while no significant differences were found between MIV, HIV(P> 0.05).⑨The expression of 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) mRNA in each part of rumen of bull calves in groups MIV, HIV were higher that of control group significantly (P< 0.05), while no significant differences were found between MIV、HIV(P>0.05). These results above indicated isovaleric acid can promote the development of rumen, that the optimum dose was 6 g/d.